Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What are the two principal characteristics of images produced by a plus lens?

1. Magnified and upright

2. Magnified and inverted

3. Diminished and upright

4. Diminished and inverted

The correct answer is: Magnified and inverted

The two principal characteristics of images produced by a plus lens are that they are magnified and inverted. A plus lens, which is a convex lens, has the ability to converge light rays. When an object is placed within the focal length of a plus lens, the rays of light diverge after passing through the lens and appear to come from a point located behind the lens, creating a virtual image that is upright and magnified. However, when the object is beyond the focal point, the image produced is real, inverted, and can be magnified, depending on the distance from the lens to the object. This characteristic of producing images that are enlarged and inverted at certain distances is essential in understanding how plus lenses function in optical devices such as magnifying glasses and some types of cameras. The other answer choices fail to represent both characteristics accurately. Diminished images suggest a minification effect that does not occur with a plus lens in typical use cases. Similarly, while an upright image can occur when the object is very close to the lens (resulting in a virtual image), it does not represent the behavior of a plus lens generating a real image at increased distances.